The systems, apparatus, and methods described herein are particularly suited for determining the constituents of such heat exchange fluids as organic acid technology coolants. Referred to as “extended life coolants,” these heat exchange fluids typically contain carboxylate salts of long-chain alkyl-based organic acids or of aromatic-based organic acids (hereinafter “acid-based corrosion inhibitors”) as corrosion inhibitors. These corrosion inhibitors inhibit corrosion of the metallic surfaces that are contacted by the heat exchange fluid. The organic acid-based corrosion inhibitors are also formulated for longer or extended service lives as compared to inorganic acid-based corrosion inhibitors. The recommended service life for “extended life coolants” (ELC) (under normal driving conditions) is commonly about five years, whereas the recommended service life for conventional coolants may be about two years.
Corrosion inhibitors that are suitable for this use are known and include carboxylate salts of long chain alkyl monocarboxylic organic acids (such as 2-ethyl hexanoic acid, octanoic acid, etc.), of dicarboxylic acids (e.g., sebacic acid), or of aromatic organic acids (such as benzoic acids and p-toluic acids). An expanded description of the type of heat exchange fluid that is a subject of the present invention and its application are provided in U.S. Pat. Nos. 5,997,763 (commonly owned with the present application) and 6,475,438. Such heat exchange fluid types are widely used. It is further noted that the subject heat exchange fluids may be aqueous and/or glycol compositions and used for automotive, heavy duty, marine and other industrial applications.
The level of corrosion inhibitor(s) present in the coolant may diminish over time. For that reason, it may be desirable to test the coolant in order to determine its continued functionality. There is not currently available a reliable and convenient method or equipment for evaluating heat exchange fluids having corrosion inhibitors therein, so as to, for example, determine the sufficiency of the corrosion inhibitor content to provide ongoing corrosion protection. Analytical methods exist, but such methods typically require equipment, facilities and/or time that are not readily available or convenient to use in the field. Moreover, used heat exchange fluids typically include an array of components, including interferents. These interferents can alter the accuracy of conventional analytical techniques.
Thus it is desirable to provide a simple, easy-to-use device that can be used to determine the sufficiency of the corrosion inhibitor content, particularly in the field, where time and operator resources are relatively scarce.